The comparative study of 4 constructed protective antigen producing strains of the classical biovar and V. cholerae strains 569 B Inaba and M41 Ogawa, used in manufacturing the cholera chemical vaccine "cholerogen-toxoid", was carried out. The study revealed that V. cholerae plasmid strains 2414 Ogawa, 2415 Inaba and nonplasmid strains 2416 Ogawa, 2417 Inaba had a higher level of production of the main protective antrigens in comparison with producer strains. They also synthesized much more (4-5 fold) cholera toxin, toxin co-regulated adhesion pili, contained protein OmpU in their outer membrane, exceeded 2- to 3-fold in the synthesis of pathogenicity enzymes (proteases, phospholipases) and synthesized the same amounts of 01 antigen, serovars Inaba and Ogawa. The use of the newly created protective-antigen producing strains in vaccine manufacturing could facilitate the preparation of a more effective cholera chemical vaccine "cholerogen-toxoid".